hi,
i am having i sony vaio notebook. earlier i was using XP and fedora 10. now when i now installed windows 7 instead of xp, fedora 10 was not working.
again i installed fedora11. if i install fedora afetr windows 7, windows 7 showed bootmgr missing. after i repaired bootmgr, windows is working fine but, fedora boot option has vanished !
how to solve this?

Not much point using F11 - unless you really have to. Try F13.
I managed to get F13 booting Win7 o.k., but I lost Win7 hibernation, so I put it back. Neosoft.net offer the free EasyBCD that will allow you to boot Fedora from the Win7 boot menu. Get the V2 - I had to use the beta for Win7, but it looks like it has now been released as the supported version.
You may need to (re-)install grub to the partition boot sector record - which you should be able to do from the install DVD. Especially easy if installing (say) F13 from scratch.

thanx, i will try it